Mutually induced filters

Abstract

A mutually induced filter for filtering radio frequency (RF) power from signals supplied to a load is described. The mutually induced filter includes a first portion connected to a first load element of the load for filtering RF power from one of the signals supplied to the first load element. The load is associated with a pedestal of a plasma chamber. The mutually induced filter further includes a second portion connected to a second load element of the load for filtering RF power from another one of the signals supplied to the second load element. The first and second portions are twisted with each other to be mutually coupled with each other to further facilitate a coupling of a resonant frequency associated with the first portion to the second portion.

The invention claimed is: 
     
       1. A system comprising:
 a first mutually induced filter configured to be coupled to a temperature controller and to a thermocouple; 
 a second mutually induced filter configured to be coupled to a power supply and a heater element of a pedestal of a plasma chamber, wherein the heater element is coupled to the thermocouple; 
 a third mutually induced filter configured to be coupled to a power source and a motor, wherein the motor is coupled to the pedestal, 
 wherein each of the first, second, and third mutually induced filters include a plurality of capacitors and a plurality of inductors, wherein the plurality of capacitors include a first capacitor and a second capacitor, wherein the plurality of inductors include a first inductor, a second inductor, and remaining inductors, wherein the plurality of inductors are twisted around each other to transfer a first frequency associated with the first capacitor and the first inductor to the second inductor and the remaining inductors and to transfer a second frequency associated with the second capacitor and the second inductor to the first inductor and the remaining inductors. 
 
     
     
       2. The system of  claim 1 , wherein the first mutually induced filter is configured to be coupled to the thermocouple via a first channel and a second channel, wherein the first mutually induced filter is configured to receive a sensed temperature signal from the thermocouple via the first channel and a reference temperature signal from the thermocouple via the second channel. 
     
     
       3. The system of  claim 2 , wherein the first mutually induced filter is configured to filter radio frequency (RF) power at the first and second frequencies from the sensed temperature signal and the reference temperature signal to output filtered signals, wherein the first mutually induced filter is configured to provide the filtered signals to the temperature controller to facilitate determination of a temperature of the heater element. 
     
     
       4. The system of  claim 1 , wherein the second mutually induced filter is configured to receive a current signal from the power supply. 
     
     
       5. The system of  claim 4 , wherein the second mutually induced filter is configured to be coupled to the heater element via a first channel and a second channel, wherein the second mutually induced filter is configured to filter radio frequency (RF) power at the first and second frequencies from the current signal to output a filtered signal and provide the filtered signal via the first channel to the heater element. 
     
     
       6. The system of  claim 1 , wherein the third mutually induced filter is configured to be coupled to the power source via a plurality of channels, wherein the third mutually induced filter is configured to receive a current signal from the power source via one of the plurality of channels. 
     
     
       7. The system of  claim 6 , wherein the third mutually induced filter is configured to filter the first and second frequencies from the current signal to output a filtered signal and provide the filtered signal to the motor. 
     
     
       8. The system of  claim 1 , wherein the first inductor is coupled in parallel to the first capacitor and the second inductor is coupled in parallel to the second capacitor. 
     
     
       9. The system of  claim 1 , wherein the plurality of inductors are twisted around each other to form a unitary body. 
     
     
       10. A plasma system comprising:
 a radio frequency (RF) power supply; 
 a match network coupled to the RF power supply; 
 a plasma chamber coupled to the match network, wherein the plasma chamber includes a showerhead and a pedestal, wherein the pedestal includes a heater element and is configured to be coupled to a motor, wherein the heater element is configured to be coupled to a thermocouple; 
 a first mutually induced filter configured to be coupled to a temperature controller and to the thermocouple; 
 a second mutually induced filter configured to be coupled to a power supply and the heater element of the pedestal; 
 a third mutually induced filter configured to be coupled to a power source and the motor, 
 wherein each of the first, second, and third mutually induced filters include a plurality of capacitors and a plurality of inductors, wherein the plurality of capacitors include a first capacitor and a second capacitor, wherein the plurality of inductors include a first inductor, a second inductor, and remaining inductors, wherein the plurality of inductors are twisted around each other to transfer a first frequency associated with the first capacitor and the first inductor to the second inductor and the remaining inductors and a second frequency associated with the second capacitor and the second inductor to the first inductor and the remaining inductors. 
 
     
     
       11. The plasma system of  claim 10 , wherein the first mutually induced filter is configured to be coupled to the thermocouple via a first channel and a second channel, wherein the first mutually induced filter is configured to receive a sensed temperature signal from the thermocouple via the first channel and a reference temperature signal from the thermocouple via the second channel. 
     
     
       12. The plasma system of  claim 11 , wherein the first mutually induced filter is configured to filter RF power at the first and second frequencies from the sensed temperature signal and the reference temperature signal to output filtered signals, wherein the first mutually induced filter is configured to provide the filtered signals to the temperature controller to facilitate determination of a temperature of the heater element. 
     
     
       13. The plasma system of  claim 10 , wherein the second mutually induced filter is configured to receive a current signal from the power supply. 
     
     
       14. The plasma system of  claim 13 , wherein the second mutually induced filter is coupled to the heater element via a first channel and a second channel, wherein the second mutually induced filter is configured to filter RF power at the first and second frequencies from the current signal to output a filtered signal and provide the filtered signal via the first channel to the heater element. 
     
     
       15. The plasma system of  claim 10 , wherein the third mutually induced filter is configured to be coupled to the power source via a plurality of channels, wherein the third mutually induced filter is configured to receive a current signal from the power source via one of the plurality of channels. 
     
     
       16. The plasma system of  claim 15 , wherein the third mutually induced filter is configured to filter the first and second frequencies from the current signal to output a filtered signal and provide the filtered signal to the motor. 
     
     
       17. The system of  claim 10 , wherein the first inductor is coupled in parallel to the first capacitor and the second inductor is coupled in parallel to the second capacitor. 
     
     
       18. A method comprising:
 receiving, by a first mutually induced filter, a plurality of signals from a thermocouple that is coupled to a heater element of a plasma chamber; 
 filtering, by the first mutually induced filter, radio frequency (RF) power from the plurality of signals received from the thermocouple to output a first plurality of filtered signals; 
 providing the first plurality of filtered signals to a temperature controller; 
 receiving, by a second mutually induced filter, a first current signal from a power supply; 
 filtering, by the second mutually induced filter, RF power from the first current signal to output a first filtered signal; 
 providing the first filtered signal to the heater element within a pedestal of the plasma chamber; 
 receiving, by a third mutually induced filter, a second current signal from a power source; 
 filtering, by the third mutually induced filter, RF power from the second current signal to output a second filtered signal; 
 providing the second filtered signal to a motor that is coupled to the pedestal of the plasma chamber. 
 
     
     
       19. The method of  claim 18 , wherein said filtering the RF power from the plurality of signals received from the thermocouple includes filtering first and second frequencies of the RF power from the plurality of signals received from the thermocouple. 
     
     
       20. The method of  claim 19 , wherein said filtering the RF power from the first current signal includes filtering first and second frequencies of the RF power from the first current signal, and said filtering the RF power from the second current signal includes filtering first and second frequencies of the RF power from the second current signal.